1. Field of the Invention
The present invention relates to light emitting modules.
2. Related Background Art
There are various types of light emitting modules, which includes one having a semiconductor light emitting device, a semiconductor light receiving device, a lens, a stem, and a lens cap. This light emitting module is constructed in a configuration wherein the semiconductor light emitting device and the semiconductor light receiving device are mounted on the stem and wherein the lens cap holding the lens is placed on the stem so as to cover the semiconductor light emitting device and the semiconductor light receiving device.
Semiconductor light emitting devices to be mounted in such light emitting modules include two types of semiconductor light emitting devices: the edge emitting type and the surface emitting type. The edge emitting type semiconductor light emitting devices are of structure in which two end faces opposed to each other constitute a resonator and in which forward light is emitted through one end face and backward light through the other end face. In the surface emitting type semiconductor light emitting devices, a pair of semiconductor layer stacks arranged in the axial direction intersecting with a light emitting surface constitute a resonator, a surface on the opposite side to the light emitting surface serves as a fixing surface to the stem, and light is emitted from the light emitting surface. Namely, the surface emitting type semiconductor light emitting devices are of structure from which it is hard to take out the backward light.